The present application relates generally to the field of a seat belt retractor for retraction and/or withdrawal by rotating a spool with an electric motor and to a seat belt unit including the retractor. More particularly, the present application relates to a seat belt retractor in which the electric motor may be controlled by an electronic control unit (ECU) and to a seat belt unit using the retractor.
Conventional seat belt units installed in vehicles restrain occupants in an emergency such as a crash or collision to reduce the likelihood the occupants may be ejected from their seats. Seat belt units include a seat belt retractor for retracting the seat belt. When not in use, the seat belt may be retracted by a spool and may be withdrawn from the spool when required (e.g., when fastened by an occupant). The seat belt retractor includes a locking mechanism that is activated in the event of an emergency to stop the rotation of the spool in the direction of seat belt withdrawal. The seat belt withdrawal is stopped so the occupant can be restrained (e.g., in the event of an emergency).